Study of alumina dissolution in cryolitic bath to the vertical soderberg (VSS) aluminum production process

Abstract

The dissolution process of alumina on industrial conditions in side-feeding VSS Soderberg technology is very complex, because it suffers interference from process variables such as: temperature and bath chemistry, physicochemical properties of alumina, amount of alumina added and bath mass available. A good control of alumina addition and process variables will contribute to keep good the current efficiency, energy consumption and reduction of the amount of sludge (undissolved alumina) formed at the bottom that in the future will compromise the flow of the electric current that will consequently reduce the efficiency of the pots. This study will show the main variables that influence the dissolution process, the behavior of the alumina concentration and the bath temperature during the feeding intervals of 2:40 and 4:00 h, the inlet temperature of the alumina and the cavity conditions due the deposition of sludge on the bottom.